The concentration of total bilirubin and activity of AST, ALT, GLDH, CPK and AP in the blood of cows before and after calving

The total bilirubin concentration and the activity of AST; ALT; GLDH, CPK, and AP were determined in the blood of cows (10 cows per group) after the f irst third and fourth calvings, 15 days prior to the expected calving date and 3 and 10 days after calving. In all three groups of cows, prior to calving, mean bilirubinaemia was with in the physiological limits. In the puerperium it increased in all the thre e groups, to a peak on day 3 after calving. The increase was significant in the cows at the first calving (6,40 mu mol/l) end very significant in the cows at the third calving (8,23 mu mol/l) -i. e. hyper-bilirubinaemia. The mean AST activity was the lowest in the blood of ail three groups of co ws prior to calving (23, 1-23, 1-34,5 IU/I). On day 3 after calving AST act ivity was significantly increased in the cows at the first (47,0 IJ/I) and third calvings (45,9 IU/I) If was also above the upper physiological limit on day 10 after calving (63,5 IJ/I). At the time there was a very significa nt difference between the cows at the first calving (38,3 IU/I) and those a t the third calving (63,5 IU/I), as well as between the cows at the third ( 63,5 IU/I) and fourth calvings (47,4 IU/I). All together; for the whole inv estigated period, in the cows at the third calving the correlation between AST activity and glucose concentration in the blood was very significant, a nd negative (r(xy) =-0,75), and between AST and ALT very significant and po sitive (r(xy)=0,49). As a whole, in all three groups of cows in late pregna ncy the correlation between AST and GLDH was very significant and positive (r(xy) = 0,57), whereas is was significant and positive (r(xy)=0,45) betwee n AST activity and bilirubin concentration in the blood.